Why is Ephesians considered higher ground than the earlier letters?
Ephesians is higher ground because it moves beyond Old Testament and Jewish references into the higher atmosphere of Christian doctrine—the Body of Christ territory. Paul, writing from Roman prison, presents the dispensation of the fullness of time, in which all things in heaven and earth are gathered together in Christ, and Gentile believers obtain an inheritance.
Les explains that Ephesians is one of the little letters Paul wrote from prison in Rome, and it takes the reader into the higher atmosphere of Christian doctrine, or into the deeper waters. Unlike earlier letters, Ephesians has no more reference to the Old Testament and no more reference to the Jew; it is higher ground and the Body of Christ territory. Les points to Ephesians 1:10, where Paul speaks of the dispensation of the administration of the fullness of time, when God will gather together in one all things in Christ, both which are in heaven and which are on earth. Gentile believers especially have obtained an inheritance, being predestinated according to the purpose of Him who worketh all things after the counsel of His own will.